Survival impact of persistent extramural venous invasion after total neoadjuvant therapy for locally advanced rectal cancer

Extramural venous invasion (EMVI) on baseline MRI is associated with poor prognosis in patients with locally advanced rectal cancer. A retrospective study at Memorial Sloan Kettering Cancer Center (New York, NY) investigated the association of persistent EMVI after total neoadjuvant therapy (TNT; chemoradiotherapy and systemic chemotherapy) with survival. Baseline EMVI was associated with poor prognosis even after TNT. EMVI regression on both post-TNT MRI and surgical pathology was associated with improved disease-free survival (HR 0.17; 95% CI 0.04-0.64) and overall survival (0.11; 0,02-0.68). Regression of pathology alone, independent of MRI EMVI status, was associated with similar improvements in survival. The authors conclude that the utility of post-TNT MRI EMVI persistence for decision-making and prognosis remains unclear.